Solar Pro 4
Solar Pro 4 is a large language model developed by Upstage designed for long-horizon tasks and agentic workflows. It features a 524,288-token context window and supports both reasoning and tool calling capabilities.
Solar Pro 4 specs and pricing
- Provider: Upstage
- Released: August 10, 2026
- Context window: 524K tokens
- Max output: 131K tokens
- Input: text
- Output: text
- Price: $0.15 input / $0.60 output per 1M tokens
- Reasoning: yes
- Tool calling: yes
What Solar Pro 4 is good at
- Processing large volumes of text documents
- Complex tasks requiring multi-step reasoning
- Automated workflows using external tools
To-dos to try with Solar Pro 4
- Analyze a 400-page technical manual to identify all safety protocols.
- Use tool calling to search a database and summarize findings from multiple reports.
- Draft a project plan based on a series of long email threads and meeting transcripts.
FAQ
- What is Solar Pro 4 primarily designed to do? It is built to handle document-intensive office productivity tasks and complex agentic workflows.
- Does this model support reasoning and external tool usage? Yes, Solar Pro 4 is equipped with built-in reasoning capabilities and supports tool calling.
- How much does Solar Pro 4 cost? Solar Pro 4 costs $0.15 per million input tokens and $0.60 per million output tokens through OpenRouter. In todo.is a typical agent step costs about 0.5 credits ($1 = 100 credits).
- What is the context window of Solar Pro 4? Solar Pro 4 can read up to 524K tokens at once and write up to 131K tokens in one reply.
- Can I use Solar Pro 4 without coding? Yes. In todo.is you pick Solar Pro 4 as your agent's model and write to-dos in plain words, on the web, the Android app, WhatsApp or Telegram. No API key needed: credits are included, or you can bring your own key.
JavaScript is required to use the todo.is app.